How can I use auto-brightness with a netcam?

Question

I am using the Instar 3010 camera (http://www.instar.de/de/in-3010-schwarz_10.html) successfully with motion-detection, recording and else. However, while the camera itself has auto-brightness (it can be switched to manual) it is not working very well. So I tried to use motion with its auto-brightness, but this does not work.

As there is no mention of commands being send to the camera, I first thought motion recalculates the picture to normalize for desired brightness. But it may actually be sending commands, but only for USB-webcams?

If so, and since the control commands are known, can the netcam controls be used for auto-brightness? How?